Field of the Invention
The present invention relates to a conveyance detection apparatus, a conveying apparatus, and a recording apparatus.
Description of the Related Art
There is a known recording apparatus that conveys a recording medium while controlling an amount of conveyance and that records an image on the recording medium. A control apparatus disclosed in Patent Document 1 includes: an imaging apparatus arranged on a conveyance route of recording paper; and a conveyance amount calculation unit that calculates an amount of conveyance of the recording paper based on an image obtained by the imaging apparatus. The imaging apparatus includes a light emitting element and an image pickup element. The light emitting element emits light to the surface of the recording paper from obliquely above, and the image pickup element images a region on the recording paper illuminated by the light emitting element while the region is enlarged by an optical system. In this case, the image pickup element images minute undulations on the surface of the recording paper as a two-dimensional image. The conveyance amount calculation unit calculates an actual amount of conveyance of the recording paper from a moving distance of an image pattern on the photographed image.
In the control apparatus of Patent Document 1, the light emitting element emits light to the surface of the recording paper from obliquely above, and the light from the light emitting element is reflected in various directions due to unevenness on the surface of the recording paper. Therefore, focusing on a specific region of the recording paper, the position of the specific region before and after the conveyance is different when the recording paper is conveyed for a predetermined distance. Therefore, it is difficult to equalize the incident angle of the light going toward the image pickup apparatus after reflection of the light from the light emitting element. As a result, the image of the specific region of the recording paper changes before and after the conveyance for the predetermined distance, and the accuracy of calculating the amount of conveyance of the recording paper may be reduced.